Advancements in computing and communications technology have significantly altered business practices regarding document creation and use. In business and personal environments, however, a substantial amount of reviewing and/or editing is still completed on printed documents. Many individuals prefer reading and/or editing documents on paper as opposed to reading and/or editing on a computer display. Nonetheless, it is often important to capture and/or track the significant amount of information that individuals add to their printed documents by using annotations and/or revisions.
In a business or personal environment where a substantial number of documents are printed, keeping track of important handwritten annotations and revision markings is problematic. Printed documents are easily lost or damaged. For example, a document can be printed and distributed at a meeting, and those attending the meeting can make annotations on the documents using a pen, pencil, highlighter, or other marking tool to capture their thoughts regarding the meeting in connection with information in the document. The document may then be folded, smudged, torn, and/or damaged in another similar manner as it is placed in a folder and transported from the meeting to a different location. Thereafter the document can lie within a stack of other documents for hours, days, months, or indefinitely.
If the handwritten annotations or revisions on a printed document are desired for later use, a significant amount of time can be required to locate a lost or misplaced document or to decipher the markings on a damaged document. Furthermore, if the annotations or revisions are meant to be applied to an electronic version of the document, significant effort must be expended to manually incorporate that information into the electronic version.
Other scenarios also exist in which it is important to capture the information added to a printed document via handwritten annotations and revisions. For instance, a vendor can prepare and fax a draft purchase order to a customer, and upon receipt of that purchase order the customer can modify contents of the faxed document by physically modifying the document using a pen or other suitable marking tool. Thereafter, the customer can relay the modified document back to the vendor by transmitting a copy using a facsimile machine. The vendor must then manually capture the new information added by the customer into his purchase order tracking system in order to make use of it. Thus in this case as well, additional effort must be expended to capture or otherwise use additional information in the form of handwritten alterations to the original document, else that information can easily be lost.
Existing systems for capturing handwritten information added to printed documents rely on special electronic hardware. Pressure-sensitive tablets record pen strokes on commodity paper pages, however the user must take care to inform the tablet when a new page has been placed on the tablet, else the tablet will record all strokes as if they belong to the previous page. Even when the tablet is properly informed of the page, it is still not aware of the page's contents, and thus it records no information about how the pen strokes relate to them.
Pens with embedded accelerometers attempt to record the physical trajectory of the pen tip, and thus record what is being written with them. However, such devices are also unaware of the contents of the page being written upon. In fact, such devices have no way to recognize the difference between pages at all. Instead, all writing surfaces are implicitly assumed to be part of one continuous surface. Pens with embedded cameras record the relationship between the pen tip's movements and a special proprietary micro pattern that is printed on the paper page. The pen can record the exact relationship of pen strokes to positions on a page, and can automatically discern the difference between pages based on the differences in the micro pattern. However, only paper with the special micro pattern printed on it can be used, thus requiring users to use not only a special pen, but special paper as well. Currently, there does not exist a system for capturing handwritten annotations and/or revision markings made on printed documents that allows the reader to use any pen and any paper of his/her choosing.